BackgroundAgeing is associated with a gradual loss of muscle strength, which in the end may have consequences for survival. Whether muscle strength and mortality risk associate in a gradual or threshold‐specific manner remains unclear. This study investigates the prospective association of muscle strength with all‐cause mortality in the oldest old.MethodsWe included 1890 adults aged ≥ 90 years (61.6% women, mean age 91.0 ± 1.5 years) from 27 European countries and Israel participating in the Survey of Health, Ageing and Retirement in Europe (SHARE) study. Muscle strength was assessed using handgrip dynamometry (unit: kilogram). Using time‐varying Cox regression with restricted cubic splines, we determined the prospective association of muscle strength with mortality, controlling for age, sex, smoking, BMI, marital status, education, geographical region and self‐perceived health.ResultsOver a mean follow‐up of 4.2 ± 2.4 years, more than half of the participants died (n = 971, 51.4%). The mean handgrip strength was 20.4 ± 8.0 kg for all participants, with men (26.7 ± 7.5 kg) showing significantly higher strength than women (16.4 ± 5.4 kg) (p < 0.001). Using the median level of muscle strength as reference (18 kg), lower and higher levels were associated in a gradual and curvilinear fashion with higher and lower mortality risk, respectively. The 10th percentile of muscle strength (10 kg) showed a hazard ratio (HR) of 1.27 (95% CI 1.13–1.43, p < 0.001). The 90th percentile (31 kg) showed an HR of 0.69 (95% CI 0.58–0.82, p < 0.001). Stratified for sex, the median levels of muscle strength were 26 kg for men and 16 kg for women. The 10th percentile of muscle strength showed HRs of 1.33 (95% CI 1.10–1.61, p < 0.001) at 15 kg for men and 1.19 (95% CI 1.05–1.35, p < 0.01) at 10 kg for women. The 90th percentile of muscle strength showed HRs of 0.75 (95% CI 0.59–0.95, p < 0.01) at 35 kg for men and 0.75 (95% CI 0.62–0.90, p < 0.001) at 23 kg for women. Sensitivity analyses, which excluded individuals who died within the first 2 years of follow‐up, confirmed the main findings.ConclusionRather than a specific threshold, muscle strength is gradually and inversely associated with mortality risk in the oldest old. As muscle strength at all ages is highly adaptive to resistance training, these findings highlight the importance of improving muscle strength in both men and women among the oldest old.

中文翻译：

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最年长老年人肌肉力量与全因死亡率的相关性：来自 28 个国家的前瞻性队列研究


背景衰老与肌肉力量的逐渐丧失有关，最终可能会对生存产生影响。肌肉力量和死亡风险是以渐进方式还是阈值特异性方式相关尚不清楚。本研究调查了肌肉力量与最年长老年人全因死亡率的前瞻性关联。方法我们纳入了来自 27 个欧洲国家和以色列的 1890 名年龄≥ 90 岁的成年人 （61.6% 的女性，平均年龄 91.0 ± 1.5 岁） 参与欧洲健康、老龄化和退休调查 （SHARE） 研究。使用握力测力法（单位：千克）评估肌肉力量。使用具有受限三次样条的时变 Cox 回归，我们确定了肌肉力量与死亡率的前瞻性关联，控制了年龄、性别、吸烟、BMI、婚姻状况、教育程度、地理区域和自我感知健康状况。结果在 4.2 ± 2.4 年的平均随访中，超过一半的参与者死亡 （n = 971， 51.4%）。所有参与者的平均握力为 20.4 ± 8.0 公斤，男性 （26.7 ± 7.5 公斤） 的握力明显高于女性 （16.4 ± 5.4 公斤） （p < 0.001）。以肌肉力量的中位水平 （18 kg） 为参考，较低和较高的水平以渐进和曲线的方式分别与较高和较低的死亡风险相关。肌肉力量的第 10 个百分位数 （10 kg） 显示风险比 （HR） 为 1.27 （95% CI 1.13-1.43，p < 0.001）。第 90 个百分位数 （31 kg） 显示 HR 为 0.69 （95% CI 0.58–0.82，p < 0.001）。按性别分层，男性肌肉力量的中位数为 26 公斤，女性为 16 公斤。肌肉力量的第 10 个百分位数显示男性 15 公斤时的 HR 为 1.33（95% CI 1.10-1.61，p < 0.001），男性为 1.19（95% CI 1.05-1.35，p < 0。01） 女性为 10 公斤。肌肉力量的第 90 个百分位数显示，男性 35 公斤时的 HR 为 0.75（95% CI 0.59-0.95，p < 0.01），女性在 23 公斤时为 0.75（95% CI 0.62-0.90，p < 0.001）。敏感性分析排除了在随访前 2 年内死亡的个体，证实了主要发现。结论肌肉力量与最年长老年人的死亡风险逐渐成反比，而不是一个特定的阈值。由于所有年龄段的肌肉力量都高度适应阻力训练，这些发现强调了提高男性和女性（最年长的老年人）肌肉力量的重要性。